It is common, in horology, to have to use gear trains are not taut, in particular where additional modules or plates are used, for example for a small seconds display.
It is then known to brake at least one wheel, for example by the pressing force of a strip-spring pressing on the arbor or on the wheel of one of the gear train wheel sets. Such braking certainly prevents the visual perception of play in the gears by the user, but generates significant friction and wear. Indeed, the braking force is not constant from one movement to another, which often means it is necessary to use excessive braking force.
One alternative consists in braking of a magnetic nature, which is not always desirable in a timepiece movement.
The use of flexible toothings is an elegant solution, where braking occurs on the toothings, but it is expensive.